A liquid crystal elastomer is a hybrid material of liquid crystals and elastomers. The liquid crystal elastomer shows a characteristic response behavior in such a manner that the liquid crystal elastomer is extended in the orientation direction by applying an external stimulus such as heat, light, electric field, and magnetic field to increase the degree of liquid crystal orientation, but the liquid crystal elastomer is shrunk by removing such a stimulus to decrease the degree of liquid crystal orientation. Thus, applications of such an elastomer to various fields such as actuators and the like have been attempted.
For example, Patent Document 1 discloses a thermotropic liquid crystal polyurethane obtained by reacting a bis(ω-hydroxyalkyleneoxy)biphenyl and 1,4-phenylene diisocyanate.
Further, Patent Document 2 discloses a polymer liquid crystal polyurethane obtained by polymerizing a diol component having a mesogenic group with a trans-1,4-cyclohexane diisocyanate.
However, in the conventional liquid crystal polyurethane, the temperature at which a liquid crystal is developed is very high and it was difficult to develop liquid crystallinity at a low temperature (near room temperature). Further, the conventional liquid crystal polyurethane did not exhibit rubbery elasticity due to increased fluidity when a liquid crystal is developed therein.